The invention is in the field of sonar. In sonar apparatus underwater transducers such as a hydrophone may receive sound energy from an underwater object such as a submarine. By arranging a plurality of hydrophones in a geometric array so that an accoustic wave from an underwater object strikes the individual hydrophones at discreet times in accordance with the geometry of the array, the azimuth of the underwater object can be determined. Most prior art sonar devices have been complex, expensive, and subject to mechanical failure. The present invention overcomes the problems of the prior art by providing a less complex, more rugged, and more efficient beam forming apparatus for a sonar device.